Method and apparatus for locking a paper pulp refiner disc



March 28, 1967 v, w. CANCILLA METHOD AND APPARATUS FOR LOCKING A PAPER PULP REFINER DISC 4 Sheets-Sheet l Filed July 2l, 1964 ATTORNE MZ' W March 28, 1967 v. w. CANCILLA 3,311,309

METHOD AND APPARATUS FOR LOCKING A PAPER PULP REFINER DISC Filed July 21. 1964 4 Sheets-Sheet 2 INVENTOR.

y YIORNEYS Mrch 28, i967 v. w. cANcxLLA METHOD AND APPARATUS FOR LOCKING A PAPER PULP REFINER DISC 4 Sheets-Sheet 5 Filed July 21, 1964 INVENTUR.

d rw ATTORNEYS March 28, 1967 v W CANClLLA 3,311,309

METHOD AND APPARATUS FOR LOCKING A PAPER PULP REFINER DISC Filed July 21, 1964 4 Sheets-Sheet 4- m. M AY/ORNEYS United States Patent O Delaware Fiied July 21, 1964, Ser. No. 384,057

19 Claims. (Cl. 241-30) The present invention relates to improvements in paper stock refiners.

More particularly, the invention contemplates providing a paper stock refiner of the four disc type where two refining plates are attached to opposite sides of a rotating disc, and -other refining plates are att-ached to a non-rotating but axially adjustable disc. The non-rotating discs define with the rotating discs first and second refining spaces with the stock iiowing radially through the spaces. During normal operation the rotating disc member is free to move laterally tow-ard either of the nonrotating discs and is maintained in its position by hydraulic pressure in the refining spaces and due to flow of the stock and reaction of the stock particles with the plates; however, during start-up and shut-down periods uneven stock fiow and unequal hydraulic pressures occur tending to move the rotating plates into actual contact with the non-rotating plates. lf this contact is made, excess and uneven disk wear will result and excessive and annoying noise will occur. Uneven disk wear will result in temporary loss of proper surface and bar edge conditions of the disks resulting in poor stock treatment.

A feature of the present invention is the provision of a force applying means in the form of a hydraulic or pneumatic expansible chamber which applies an axial force to the rotating disc moving it to a stop position against an adjustable pre-set stop which locates and locks the rotating disc at a neutral non-interfering position between the non-rotating discs during start-up or shutdown periods. During these ti-mes unequal pressures and non-uniform ows exist and the tendency of the rotor disc to displace is nullified. The unique positioning apparatus can 'be employed in various environments but is especially useful in papermaking refiners for treating cellulose fibers or paper stock and the invention will be described and shown in connection with such use.

lt is an object of the present invention to provide a -paper stock rener of the type above described in which noise and excessive wear heretofore encountered due to unequal hydraulic forces at the beginning of operation and at `the termination of operation are substantially eliminated.

A further object of the invention is to provide a paper stock refiner of the type above described in which temporary loss of proper surface and bar edge conditions of the refining disks caused yby disk to disk contact during start-up and shut-down periods is substantially eliminated.

Another object of the invention is to provide unique mechanism for use with a four plate refiner having a central axially floating rotor, which will controllably fix the position of the rotor during initial start-up of the mechanism when surges of stock flow through the machine and unequal fiows occur Aand when hydraulic pressures in the refining spaces are unbalanced and tend to improperly displace the rotor.

Yet, another object of the invention is to provide an improved paper stock four disc refiner mechanism wherein initial wear and noise which occur at the starting and shut-down are eliminated without interfering with the optimum and advantageous normal operation of the mechanism.

"ice

Other objects, advantages and features will become more apparent with the teachings of the principles of the present invention in connection with the disclosure of s the preferred embodiments thereof in the specification,

claims and drawings, in which:

FIGURES l and 2 are vertical sectional views of a refiner constructed yand operating in accordance with the principles of the present invention, with the figures being viewed together and showing the left and right hand ends of the machine respectively;

FIGURE 3 is a sectional view taken substantially along :line lil-lll of FIGURE 2; and

FIGURE 4 is a vertical sectional view showing the left `hand end of la refiner in section, with the view being similar to FIGURE 1 but showing a modified arrangement.

On the drawings:

As shown in FIGURES 1 and 2, the refiner 10 is enclosed in a housing 11. The refiner is of the type which may be generally referred to as a four disc refiner wherein four opposed plates define dual refining spaces. A center disc or rotor 12 carries refining plates 13 and 14 suitably secured thereto. At each side of the rotor are stationary annular refining plates 15 and 16 which are suitably secured to parts of the housing 11 so as to be non-rotatable. The plates have facing refining faces, as will be fully appreciated by those versed in the art, so as to define radial annular refining spaces 17 and 18 therebetween.

Liquid paper stock, or other material being refined,- enters into an inlet passage 19 and flows to an annular inlet chamber 2@ so that the stock fiows outwardly through a first refining space 17. The stock then flows into an annular outer intermediate chamber 21 and into the second refining vspace 1S. An outlet passage 34 from the chamber 21 is provided for certain operations of the refiner such as draining for clean out purposes or recirculation and removal of stock during normal operation, and this is `shown as closed by a cover plate 34a.

The refined stock after passing through the second refining space 1S fiows into an annular outlet chamber 22 and out through an outlet passage 23.

The outlet passage extends through an opening 27 in an end housing 24. The end housing 24 supports an adjustment mechanism which axially adjusts the position of the stationary refining plate 16 to thereby determine the width of the refining spaces 17 and 13.

The rotor 12, with its refining plates 13 and 14, is carried ffoatingly during normal operation and will retain a balanced position due to the hydraulic pressures in the refining spaces 17 and 18 which act against the refining faces of the plates 13 and 14. The hydraulic pressures in these spaces 17 and 18 maintain the rotor 12 substantially centered due to the reaction of the stock being refined and the substantially uniform flow through the spaces 17 and 1S. However, during start-up and shutdown fiow to the spaces is not uniform, and the hydaulic pressures are not uniform. If the rotor 12 becomes displaced too `far axially so that the faces of the rotating and non-rotating discs engage7 substantial unwanted wear of the refining plate faces will occur resulting in loss of proper surface and bar edge conditions and undesirable noise will also result.

A feature of the present invention is the provision of a method and structure for operating in accordance with the method that maintains the rotor disc 12 at a neutral position which is generally between the non-rotating plates 15 and 16, and so that the refining faces will not engage. The disc locking arrangement does not interfere with the normal operation of the rener and can be taken out of operation automatically such as by means of a s limit switch, or manually so that it functions only during start-up and shut-down. The device is fully operative without interference with mechanism for adjusting the refining space and refining operation of the refiner.

For adjusting the refining space, the non-rotating disc 16 is carried on a movable disc support 26. Seals 16a and 16b permit shifting of the non-rotating plate 16 and its support 26 without leakage.

The support 26 is connected to an axially movable support shaft which has a threaded end Z9. The threaded end is axially held in a predetermined position by a rotatable nut 28 that is rigidly supported in bearings 23a in the housing part 24. The nut is driven in rotation by a worm gear 28b driven by a worm 3%.

As shown in FIGURES 2 and 3, the worm 3G is rotatably supported in end bearings and is operated either by a motor 32 through a clutch 31, or by a hand wheel 33. For manual operation by the hand wheel 33, the clutch 31 is disengaged. The motor 32 can be automatically operated such as by control mechanism which operates responsive to other functions or conditions in the machine, and a stock characteristic sensing device may operate the motor for obtaining a predetermined output of the refiner and the axial position of the non-rotating plate 16 is set in accordance with an automatic control signal, and the axially floating disc rotor 12 will automatically adjust by shifting axially in accordance with the hydraulic pressures acting on the faces of the refining plates 13 and 14 thus affecting the flow of stock through the plates. A similar adjusting device may of course be provided for the stationary disc 15 so as to axially adjust its position.

The disc 12, FIGURE 2, is suitably secured to a rotor hub 37 such as by bolts 36 and the hub mounted on a rotor shaft 38. The shaft is suitably supported in bearings `and is provided with a seal 39 which prevents stock from leaking from the inlet chamber 2@ alongthe shaft 38.

As shown in FIGURE 1, the shaft 38 is supported in a front bearing 48 slidably mounted in a cylindrical suppo1t 41 on the housing 11.

For driving the refiner the arrangement of FIGURES 1 and 2 embodies an enclosed motor having a stator 43 enclosed by the housing 11 and a rotor 42 secured to the shaft 38. The rotor 42 shifts axially with the shaft in its movement with the rotor disc 12.

The rear end of the shaft 18 is supported in a bearing 44 which slides axially in a housing hub 48 having a cylindrical opening therein.

During start-up, the shaft 38 and rotor disc 12 are locked in a neutral position by operation of a fluid pressure actuated device shown as being preferably in the form of a bellows 46. A controlled fluid inlet 46a supplies fluid such as mill air pressure to the bellows 46 during start-up and shut-down periods and vents the bellows so that it does not apply pressure to the shaft 38 during normal operation of the refiner. The bellows is mounted within a rigid cap 47 on the frame and is attached to a sliding housing 45 for the bearing 44. The bellows thus provides a fluid pressure chamber having a movable wall which is operatively attached to the rotor.

A stop means is provided which limits the axial movement of the shaft 38 acting against the bellows 46 so that the disc 12 is locked in a neutral position. The stop is shown in a preferred simplified form as embodying a stop bolt 49 which is adjustably threaded into the rigid housing member 48. A shoulder 50 on the slidable bearing housing 45 engages the head of `the bolt 49, to stop axial movement of the shaft 38 in its neutral position. The stop bolt 49 is adjustably threaded in or out to a predetermined locked position of the disc rotor 12, and a suitable opening, not shown, will be provided in the cap 47 so that the stop bolt 49' is accessible with a wrench.

FIGURE 4 shows an arrangement wherein a locking force is applied by means positioned axially outwardly of the shaft whereas the bellows of FIGURE 1 is coaxial with `the shaft 38. In FIGURE 4, the mechanism is driven by an external motor rather than an internally housed motor as with FIGURE 1. Either rotor locking mechanism of FIGURE 1 or 2 or FIGURE 4 may be employed with an internal or external drive motor. A shaft 38 has a front bearing supported in a bearing housing 4G slidably supported in a cylindrical support 41 in a housing 11.

The rear bearing 57 is supported in a bearing sleeve 58 slidable in -a bearing guide 59. The shaft 38 has a shaft extension 55 which is splined or keyed at 56 for attaching other drive means for the reflner.

Axial locking pressure for the shaft is applied by fluid operated bellows 66 and 61 which are rigidly mounted on a support 63 connected to the housing 11. The other end of the bellows 60 and 61 operates on a yoke 64 which is secured to the bearing sleeve 58 so as to shift the bearing therewith and thereby shift the shaft 38. The bearing 57 is locked to vthe shaft 38 such as by being pressed up against a shoulder 57a on the shaft 38 and locked against the shoulder by a bearing locking ring 5711. The bearing is similarly locked to the bearing sleeve 58 by the sleeve being provided with a shoulder 57 b and receiving a bearing locking ring 58h bolted thereto.

The stop position of the shaft 38 is determined by a stop bolt 65 adjustably threaded into the hub of the frame 11 and having a head which engages a stop surface 64a on the yoke 64. The stop bolt 65 may of course be alternatively threaded into the surface 64a and forced into engagement with the hub 11'.

The stop position of the rotor disc 12 is preferably substantially intermediate the non-rotating refining plates 15 and 16, but in one form preferably is further to the right (in the position of FIGURE 2) than its location during normal operation. Thus, during start-up or shutdown, the bellows 46 of FIGURE l will hold the disc rotor 12 slightly to the right of its normal position, and during normal running when the bellows 46 is vented, the rotor can run at a free floating position without engaging the stop bolt 49. In other words, in normal position the stop shoulder 50 will be slightly away from the head of the stop bolt 49 thus making it unnecessary to adjust the stop bolt and permitting the free flowing operation of the disc rotoi 12. The same arrangement will be employed with FIGURE 4, and the bellows 60 and 61 will be pressurized by suitable fluid pressure lines, not shown.

In operation, with the larrangement of FIGURES 1-3, the bellows 46 will be pressurized to shift the 'rotor shaft 38 to the right until the shoulder 50 engages the stop bolt 49. This will hold the rotor disc 12 in a neutral position as long as the operator so desires. The motor rotor 42 shifts with the shaft and this does not adversely affect operation. In this position, there is no danger of the refining faces engaging, and a flow surge of paper stock can be admitted into the inlet passage 19 to flow through the refining spaces 17 and 18 without danger of the hydraulic forces shifting the rotor plates 13 and 14 up against either of the non-rotating refining plates 15 and 16. When the stock flow is stabilized, the bellows 46 is vented to atmospheric air so that the rotor 12 can float and maintain its neutral running position due to the hydraulic forces in the refining spaces 17 and 18. The width of the refining spaces will be adjusted by rotating the adjusting nut 28 through the worm gear 28h. At shutdown when the stock flow is to be stopped, the bellows 46 is again pressurized to lock the rotor at the neutral position.

Thus, it will be seen that I have provided an improved rotary rener of the four disc type which meets the objectives and advantages above set forth. The mechanism avoids disadvantages heretofore existent in the art and extends the operating life of the refiner plates avoid` ing the disadvantages of engagement between refining discs.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, `and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. In a paper stock refiner the combination comprising:

a refiner rotor having a first and second refiner plate thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refiner plate defining a first refining space with said first rotor plate, a second stator having a second plate defining a second refining space with the second rotor plate,

said stator and rotor relatively axially movable for changing the width of said refining spaces with movement,

a fluid pressure chamber member having a moveable wall member with one of the members operatively connected to the stator and the other operatively connected to the rotor, means directing pressurized fluid to said chamber for moving the rotor and changing said refining spaces, and stop means acting against said chamber Wall member limiting movement of said rotor at a neutral position for preventing engagement between rotor and stator plates during starting when hydraulic pressures are unequal.

2. In a paper stock refiner the combination comprising:

a refiner rotor having a first and a second refiner plate thereon,

a shaft means supporting the rotor and Vadapted for being rotationally driven,

a refiner stator having a first refiner plate defining a first refining space with said first rotor plate, `a second stator having a second plate defining a second refining space with the second rotor plate,

said stator and rotor relatively axially movable for changing the width of said refining spaces with movement,

a fluid pressure chamber member having a movable wall member with one of the members operatively connected to the stator and the other operatively connected to the rotor, means directing pressurized fluid to said chamber for moving the rotor and changing said refining spaces,

stop means acting against said chamber Wall member limiting movement of said rotor at a neutral .position for preventing engagement between rotor and stator plates during starting when hydraulic pressures are unequal,

and means for adjusting the location of said stop means.

3. In a paper stock refiner the combination comprising:

a refiner rotor having first and second radial refinhig faces thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refining face defining a first refining space with said first rotor face,

la second stator refining face defining a second refining space with the second rotor face,

said stator and rotor relatively axially movable changing the width of said refining spaces with said movement,

a bellows member connected to the rotor shaft means for holding the rotor in a positive predetermined neutral position during start-up land counteracting hydraulic pressures between said refining faces, and

stop means limiting movement of the rotor for holding it in said predetermined neutral position.

4. In a paper stock refiner the combination comprising:

a refiner rotor having first and second radial rening faces thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refining face defining a first refining space with said first rotor face,

a second stator refining face dening a second refining space with the second rotor face,

said stator and rotor relatively axially movable changing the Width of said refining spaces with said movement,

pressure balancing means operatively connected to said rotor holding the rotor axially positioned in a positive predetermined location with said rotor and stator refining faces separated, Iand stop means limiting axial movement of the rotor for holding it in said positive predetermined location.

5. In a paper stock refiner the combination comprising:

a refiner rotor having first and second radial refining faces thereon,

1a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refining face defining a first refining space with said first rotor face,

a second stator refining face defining a second refining space with the second rotor face,

said stator and rotor relatively axially movable changing the width of said refining spaces with said movement,

a pressure chamber having a movable wall operatively connected to the rotor and substantial coaxial therewith applying an axial balancing force to the rotor counteracting hydraulic forces between said faces, and

stop means acting against said pressure chamber wall limiting axial movement of said rotor.

6. In a paper stock refiner the combination comprising:

a refiner rotor having first and second radial refining faces thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having `a first refining face defining a first refining space with said first rotor face,

a second stator rening face defining a second refining space with the second rotor face,

said stator and rotor relatively axially movable changing the width of said refining spaces with said movement,

a plurality of pressure chambers each having movable walls operatively connected to the rotor substantially at diametrically opposed locations displaced from the rotor axis applying axially balancing forces to the rotor counteracting hydraulic forces between said faces, and

stop means limiting axial movement of said rotor.

7. A paper stock refining mechanism comprising in combination:

first and second refining spaces defined between first and second plates of stators and a rotor therebetween,

a shaft rotatably supporting the rotor and supported for axial movement relative to the stator for changing the refining spaces,

means applying an axial force to the rotor shaft for moving the rotor laxially relative to the stators,

and a stop means including a bolt member slidably extending through an opening in a plate member with a head engaging the plate member at a stop position and being adjustable to change said position,

said stop means acting against said force applying means having one member fixed in location and the other member operatively connected to said shaft to limit axial movement ofthe rotor.

8. In a paper stock refiner the combination comprising:

a refiner rotor having a first and a second refiner plate thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refiner plate defining a first space with said first rotor plate,

a second stator having a second plate defining a second refining space with the second rotor plate,

said stator and rotor relatively axially movable for changing the width of said refining spaces with movement,

a fluid pressure chamber member having a movable wall member with one of the members operatively connected to the stator and the other operatively connected to the rotor, means directing pressurized fiuid through said chamber for moving the rotor and changing said refining spaces, stop means acting against said pressure chamber wall member limiting movement of said rotor at a neutral position for preventing engagement between rotor and stator plates during starting and stopping when hydraulic pressures are unequal, a housing enclosing said rotor and stators, and

a motor enclosed in said housing having a motor rotor and motor stator coaxial with the shaft means and the stator being mounted on the shaft means.

9. In a paper stock refiner the combination compris-ing:

a refiner rotor having a first and a second refiner plate thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refiner plate defining a first refining space with said first rotor plate,

a second stator having a second plate defining a second refining space with the second rotor plate,

said stator and rotor relatively axially movable for changing the width of said refining spaces with movement,

a fluid pressure chamber member having a movable wall member with one of the members operatively connected to the stator and the other operatively connected to the rotor,

means directing pressurized fluid through said chamber for moving the rotor and changing said refining spaces,

stop means acting against said chamber wall member limiting movement of said rotor at a neutral position for prevent-ing engagement between rotor and stator plate during starting when hydraulic pressures are unequal,

a housing enclosing said rotor and stators,

and a drive means externally of said housing connected for driving said shaft means in rotation.

10. A paper stock refining apparatus comprising in combination:

a refiner rotor having refining plates thereon,

first and second stators axially outwardly of the rotor having refining plates defining first and second rotor spaces,

a rigid supporting housing rotatably carrying said rotor on bearings therein,

a fluid pressure chamber rigidly mounted in said housing and having a movable wall connected to the rotor for applying an axial displacing -for-ce to the rotor, and

stop means acting against said chamber wall rigidly mounted on the housing limiting the axial displacement of the rotor to a neutral position wherein it will not interfere with the stators during start-up when hydraulic pressures are unbalanced.

11. In a paper refiner the combination comprising:

a refiner rotor having a first and a second refiner plate thereon,

a shaft means supporting the rotor and adapted for being rotationally driven,

a refiner stator having a first refiner plate defining a first refining space with said first rotor plate,

a second stator having a second plate defining a second refining space with the second rotor plate,

S said stator and rotor relatively axially movable for changing the width of said refining spaces with movement,

means for adjusting the distance between said stators for adjusting the width of said refining spaces with the rotor operating at a hydraulically balanced position therebetween during normal running operation with fiuid stock in said spaces,

a liuid pressure chamber member having a movable wall member with one of the members operatively connected to the stator and the other operatively connected to the rotor,

means directing pressurized fluid through said chamber for moving the rotor and changing said refining spaces, and

stop means acting against said chamber Wall member limiting movement of said rotor at a neutral position for preventing engagement between rotor and stator plates during starting when hydraulic presssures are unequal.

12. A paper stock refining apparatus comprising in combination:

a refiner rotor having radial refining plates thereon,

first and second retiner'stators having refining plates thereon defining with said rotor first and second refining spaces,

a stock inlet passage leading into the radial inner edge of said first refining space.

a stock outlet passage leading from the radial inner edge of the second refining space,

an annular chamber surrounding the rotor and stators for directing stock from thte first to the second space, and

means locking said rotor at an intermediate axial position relative to the stators during start-up when hydraulic pressures are unequal.

13. A paper stock refiner structure comprising in cornbination:

a refiner rotor,

first and second refiner stators coaxial therewith with said rotor and stators having refining plates defining first and second refining spaces therebetween,

a housing supporting said rotor and stators with said first stator being fixed and the rotor being axially movable between the stators,

means for axially adjusting the position of the second stator relative to the first,

means applying an axial force to the rotor moving it toward the second stator, and

stop means limiting movement of the stator from the force means at a position substantially intermediate the stators during start-up when hydraulic pressures are unequal.

14. A paper stock refiner mechanism comprising in combination:

a rotor having radial refining plates thereon,

first and second stators on the sides of the rotor having plates defining first and second rening spaces therewith,

a stock inlet communicating with said first space at the radial inner edge thereof,

an outlet communicating with said second space at the radial inner edge thereof,

a chamber leading from the outer edge of the first to the outer edge of the second space,

means applying a resilient force to said rotor in the direction of flow from the first to second space, and

stop 'means limiting axial movement of the rotor from said force means.

15. A paper stock refiner comprising in combination:

a rotor having first and second refining plates on the radial surfaces thereof,

a shaft supporting said rotor,

a housing enclosing said rotor having spaced supporting bearings for said shaft,

motor means driving said shaft and rotor in rotation,

a first stator rening plate supported in said housing defining a iirst refining space with the rotor,

a second stator rening plate axially movable in said housing deiining a second refining space with said rotor,

means for adjusting the axial position of said second plate,

an inlet passage in said housing leading through the radial inner edge of said first refining space,

an annular outer communicating chamber between said lirst and second spaces leading between the outer radial edge thereof,

a stock take-off passage communicating with said chamber for receiving stock after it has iiowed through said irst refining space,

an outlet passage leading from the radial inner edge of said second passage for receiving stock after it has flowed through both said first and second rening spaces.

a pressure iniiatable bellows rigidly supported in said housing and having a movable wall operatively connected to said shaft for applying an axial force thereto urging the rotor toward said second plate,

a stop bolt adjustable mounted in said housing and operatively engageable by the shaft acting against said bellows to limit movement of the rotor at a location intermediate the stator plates preventing interference between the rotor and stator plates during strat-up when hydraulic pressures are unbalanced.

16. The method of operating a paper stock reiiner having opposed non-rotating refner plates with rotating plates therebetween which comprises the steps of locking the position of the rotor intermediate the non-rotating plates while starting up and during times when hydraulic pressures on the plates are unbalanced due t0 initial incoming iiow of stock and until stable running operation is reached.

17. The method of operating a paper stock refiner having opposed non-rotating reliner plates with rotating plates therebetween which comprises applying an axial force to the rotating plates in one axial direction, and stopping the axial movement of the rotor plates at a position between the non-rotating plates preventing interference therebetween during start-up, and releasing said force when normal running operation is achieved.

i8. The method of operating a paper stock reiiner having opposed stator plates with rotor plates therebetween deiining sequential irst and second refining spaces with stock liowing from the first to the second space which comprises the steps:

applying a yielding force to the rotating plates in the direction of stock iiow from the rst to the second space, and

applying a positive stop against said force locating the rotor plates at an intermediate position.

19. The metho-d of operating a paper stock reiiner having iirst and second stator plates with a rotor having plates therebetween defining first and second sequential reiining spaces, the method comprising the steps of applying a force to the rotor urging it toward the second plate,

applying a positive stop against said torce at a location where the rotor is closer to the second plate than the irst but not interfering therewith, and

releasing said force after start-up and after normal hydraulic pressures in said spaces have been obtained.

References Cited by the Examiner UNITED STATES PATENTS 471,345 3/1892 Stover 241-32 2,244,996 6/1941 Laird 241-32 2,743,874 5/1956 Asplund 241-256 X 3,118,622 1/1964 `iones 241-255 X ANDREW R. JUHAsz, Primm Examiner. 

16. THE METHOD OF OPERATING A PAPER STOCK REFINER HAVING OPPOSED NON-ROTATING REFINER PLATES WITH ROTATING PLATES THEREBETWEEN WHICH COMPRISES THE STEPS OF LOCKING THE POSITION OF THE ROTOR INTERMEDIATE THE NON-ROTATING PLATES WHILE STARTING UP AND DURING TIMES WHEN HYDRAULIC PRESSURES ON THE PLATES ARE UNBALANCED DUE TO INITIAL INCOMING FLOW OF STOCK AND UNTIL STABLE RUNNING OPERATION IS REACHED. 